dual_sport_dork , 4 hours ago

All modern guns* have firing pins. The firing pin is the part that pokes the primer to set off the cartridge.

However, they may or may not have externally accessible hammers. Some are on the outside and can be cocked with a thumb, e.g. the 1911 or Beretta M92/M9 and most revolvers. Some have internal hammers which are fully encapsulated by the slide or receiver and can’t be directly accessed without disassembly. This includes many modern rifles, for instance. And further, some guns may have “strikers” rather than hammers. The difference is a bit pedantic and basically boils down to strikers rarely being externally accessible, and usually their spring action being linear rather than the rotation movement of a hammer. Some people argue that any internal hammer is actually a striker. Others ague that the mechanism on, say, a Mosin-Nagant is a hammer and not a striker even though its action is clearly linear but it is externally accessible, etc., etc.

Regardless of which you have, a hammer or a striker, the end result is the same: Some manner of spring loaded mechanical dingus whacks into the firing pin, which in turn strikes the primer, which ignites and fires the shot.

(* Before additional pedantry rears its head, that is to say all modern fixed cartridge loading, primer fired guns. We’ll leave out any exotic novelties like guns firing caseless ammunition or electrically initiated primers, etc., which essentially do not exist as consumer products yet. This also excludes reproduction percussion cap guns, which may be “modern” in that they’re still being made, but utilize pre-turn-of-the-centruy mechanisms that usually involve the hammer landing directly on a percussion cap with no firing pin in between.)